Semiconductor devices, e.g. appropriate, integrated (analog or digital) computing circuits, semiconductor memory devices such as functional memory devices (PLAs, PALs, etc.) and table memory devices, e.g. ROMs or RAMS, in particular SRAMs and DRAMs) comprise a plurality of output pads for outputting data generated in the respective semiconductor device.
The output pads are connected with a device driving the corresponding output signals, i.e. a driver device.
Each driver device may, for instance, comprise a pull-up and a pull-down circuit which are connected in series, wherein the pull-up circuit may e.g. be connected to the supply voltage, and the pull-down circuit may e.g. be connected to the ground, and wherein—for the driving of a “logically high” output signal—the pull-up circuit may be switched on and the pull-down circuit may be switched off, and—for the driving of a “logically low” output signal—the pull-up circuit may be switched off and the pull-down circuit may be switched on.
For linearization of the driver behavior, a correspondingly large resistor, in particular an n-diffusion resistor, may be connected between a corresponding driver device and the respective output pad.
For generating an n-diffusion resistor, the corresponding region on the semiconductor device or the chip, respectively, is—relatively strongly—n-doped.
The resistance value of the respective n-diffusion resistor may, for instance, by set to the respectively desired amount by correspondingly selecting the length (or the breadth or the width, respectively) of the n-diffusion resistor—the longer (or broader) the n-diffusion resistor is, the higher (or lower) is the resulting resistance value.
For technological reasons, the—relatively strongly n-doped—diffusion regions of the n-diffusion resistors are embedded in a weaker n-doped region, i.e. a so-called wn-well.
In order to save chip space, several (in particular all) n-diffusion resistors are, as a rule, arranged—side by side—in one single wn-well.
Consequently, the n-diffusion resistors are—via the parasitic resistor formed by the wn-well—connected with one another, so that adjacent n-diffusion resistors mutually influence each other in their respective—effectively—resulting resistance value.
This influence is the higher, the greater the difference between the resistance values of respectively adjacent n-diffusion resistors is.
For this reason, the distance between respectively adjacent n-diffusion resistors must be chosen relatively large in prior art (in particular in the case of a relatively great difference between the resistance values).
This—relatively large—distance between the n-diffusion resistors leads to a relatively large chip space needed altogether for the arrangement of the n-diffusion resistors.